Study remains the most common reason for migrating to the UK, but the numbers fell to 197,000 from 239,000 the previous year.

The number of migrants coming to the UK from Poland and other new EU countries also fell, from 86,000 the previous year to 62,000 - the lowest level since they joined the EU in 2004.

The end of restrictions imposed by other EU countries on these citizens may have diverted some of them elsewhere, including Germany, the ONS said.

The change will add to the complications in predicting how many migrants from Bulgaria and Romania will head to the UK when work restrictions are lifted in January next year.

Prime Minister David Cameron and Theresa May, the Home Secretary, have pledged to cut net migration to the tens of thousands before the next election in 2015 and have brought in a series of measures to tackle abuse in the immigration system.

Analysts at the Migration Observatory at the University of Oxford said Thursday’s figures showed the Government was more than half way to achieving its goal.

But Dr Scott Blinder, the centre’s acting director, warned that the further cuts which were needed were greater than those projected in the Government’s own impact assessment for its policy changes.

He said: “This could still be a difficult task.”

However, Mark Harper, the Immigration Minister, said: “Our tough reforms are having an impact in all the right places - we have tightened the routes where abuse was rife and overall numbers are down as a result.

“But sponsored student visa applications for our world-class university sector are up and the numbers of skilled people being sponsored by UK employers in sectors such as IT and science have also increased.”

Sponsored visa applications rose 3% in the university sector, but fell 62%, 69% and 14% for further education, English language schools and independent schools respectively.

Sir Andrew Green, chairman of the pressure group Migration Watch UK, said the figures showed universities have been “crying wolf” over fears the Government’s reforms were deterring genuine students.

“Not only is it clear evidence that the Government’s policies are taking effect, but they’re doing so in exactly the way they intended,” Sir Andrew said.

“Visas for university students are up, but for colleges where all the abuse was thought to take place they’re sharply down, so the universities have been crying wolf.”

But the Institute for Public Policy Research warned that falls driven by fewer overseas students would not continue.

Sarah Mulley, the think-tank’s associate director, said the decline “will only have a short term effect on net migration”.

“Because most students stay in the UK only for a short time, reduced immigration now will mean reduced emigration in the future, which by 2015 could partially reverse the falls we are seeing today,” she said.

She warned that “more drastic cuts to student numbers would be needed to make further progress towards the Government’s target”.

The fall in net migration was also driven by a significant decrease in the number of immigrants arriving from New Commonwealth countries, such as Botswana, Bangladesh, India and Pakistan, where previous studies have identified abuse.

Some 117,000 immigrants from New Commonwealth countries arrived in the UK in the year to June, down 30% or 51,000 from 168,000 in the previous year.